Posted
by
ScuttleMonkeyon Wednesday July 26, 2006 @07:15PM
from the decorative-corporate-logo-pools dept.

Chancer writes "Engadget is reporting on Japanese scientists who have found a way to 'write' characters on the surface of water using waves. This looks very cool - but the time required to change character seems very high (15-30 seconds). From the article: 'Liquid-based displays are nothing new -- in a vertical orientation, at least -- but apparently it's a lot more difficult to coax a standing pool of water into forming recognizable shapes and characters.'"

I believe that phrase likely originated with the poet John Keats [wikipedia.org]:

He died on February 23, 1821 and was buried in the Protestant Cemetery, Rome. His last request was followed, and thus he was buried under a tomb stone reading, "Here lies one whose name was writ in water."

Actually, I don't. I just happen to have recently been reading the (science fiction) Hyperion books [iblist.com] by Dan Simmons (not to be confused with an epic poem by Keats of the same name), in which Keats (or, actually, a reconstruction of Keats meant to be similar to the original historical Keats) plays a significant role.

That only shows how useful SF can be!;-)Read the hyperion-serie myself several years ago, and found it to be quite good. Especially the first two books are definately above the SF-average (and I've read a lot of SF and fanatsy).

No doubt some day, someone will make a movie out of it, and there will be a 80% chance they screw it up big time... after all, I know only of a handful of films that are equal or better then the books they're based on.

Permanent, easy to read pregnancy tests in every toilet. Ok, maybe womens' washrooms only.
When a women sees the "U R Preggers" in the toilet water, she has the option to purchase a morning after pill from the dispenser built into the tank.

The toilets could also upload the bowl results through the tubes, although the internets might get blocked by all that tp.

A freind of mine once wrote a message with a much lower refresh rate... he planted trees. Somewhere in northeastern Washington, aliens (or pilots) may be startled to see a certain naughty word beginning with "f" spelled out over a couple acres.

Hmm. Actually, I ought to get the coordinates and check google maps...

A freind of mine once wrote a message with a much lower refresh rate... he planted trees. Somewhere in northeastern Washington, aliens (or pilots) may be startled to see a certain naughty word beginning with "f" spelled out over a couple acres.

Actually in Germany there is a giant swastika in the Black Forests the was crreated by the Nazis during the 1930s. It's a very interesting concept.

For example, writing a word in water and having the perimeter of the pool recognize the waves, and convert it to digital text. Microscopically, that could actually have a use with a liquid enclosed touchscreen.

That would be cool! However, it seems a little harder than this - in fact, it may not be possible.

If I understand the article (it's short on details) they're displaying an image by decomposing it into Bessel functions (like the Fourier decomposition in JPEG compression) and then having elements oscillate at different frequencies to recreate the shape. Bessel functions are the natural set of orthogonal functions for cylindrical symmetry - which is what the tank has.

Interesting, but why would someone want or need to do this? I fail to see any problem or application that this could possibly solve or address.Wait. I could be in swimming pool, and the lifeguards could use this tool to "write" in the water to get out, or that someone is drowning, or that there is a sale on cold beers at the concession stand. That's it... advertising... there is an applicaton! Maybe I answered my own question.

In any case, for those that RTFA, it would be quite a scary pool to be swimmin

It's been said before, and even on the original article I read about this, but the applications are mostly for places like Disneyland and Casinos. Couple this with a light-show and a cool fountain, you get the idea. It's purely artistic.

you could also use the idea on more substances like say.. epoxy or rasien. to create shapes in a certian form quicker than some one could carve one.. i am thinking for master molds for boats and stuff.. where it takes months to a year to make the master.. if you could put in a plotted file and get a close shape form this thing.. even if it took it a week to make the shape it would be worth every bit of $

That's an interesting idea, but I'm not sure that'd be possible with the 2D nature of the display. Perhaps I'm confused, but this only produces a surface image, it doesn't produce a 3D model with the water.

well it does create a 3D shape one top of the flat plane of water the 2d shape can't curve back on it's self as it would fall but if ever took a look at a boat and flipped it upside down you would see that you would never need it to.

the idea is to get something close quickly instead of having to lay it out in wood - shape it and clean it.. if you could make something close - pop a mold of it then you can make fine changes to the mold.

Further to the parent, the lack of an existing problem or application should not immediately be a reason to not explore a phenomenom or similar. Very frequently people come up with a problem that they would like solved (eg: cryptography), and find that much of the solution already exists independent of the application (eg: number theory).

In any case, for those that RTFA, it would be quite a scary pool to be swimming in, with all those magnents around the edge of the pool.

I don't think they're magnets -- they're more `actuators' or `wave generators' (and probably do contain magnets.) But point taken...

In any event, a fast fourier transform (FFT) can be used to describe any arbitrary waveform as a series of frequencies and amplitudes (and phases I guess) -- I guess that this is just people doing the opposite, using a series of wave

Write a message in clouds (yes, that's a big jump), for example? Think of the advertising opportunities!

AARRGGHH!!!

So, it isn't enough that every square centimeter of every wall is full of flashing, blinking, annoying crap that tries to make me buy something; now I can't even watch the sky without some moronic vitamin supplement ad getting in the way ?

Or, once script kiddies get to the wave generators, goatse clouds. Hmm... Now that I think of it, maybe they could put the goatse cloud somewhere it f

Leela: "Didn't you have ads in the 20th century?"Fry: "Well sure, but not in our dreams! Only on tv and radio...and in magazines...and movies. And at ball games, on buses, and milk cartons, and t-shirts, and bananas, and written on the sky. But not in dreams! No sirree."

using formulas known as Bessel functions to cut the processing time down to between 15 and 30 seconds and form characters

That sure makes it sound like the calculations involved are so great that the computer takes that long to process (as opposed to a physical delay in the hardware or medium). Certainly that could be reduced substantially either by optimization or throwing more CPUs at the problem. If that is indeed the issue then they could also precalculate the math for various shapes, and recall them instantly on demand. I also wonder if this is a purely virtual simulation inside the software, or if the system requires feedback from sensors in the real world to fine-tune the oscillations to produce the desired effect. In that case it may take that much time to stabilize the system because of chaos and the like. I have a hunch that must be what's going on, because certainly these people are smart enough and have enough funding so that processing speed alone isn't the issue.

Part of the trouble is that these things are NOT stationary. There's only once in a long time that all of the waves produced by those actuators end up forming the characters they want them to, AND all the rest of the surface is smooth. And that can only be done with some sophisticated feedback as to what waves are present. I haven't read their paper, but I suspect they either sense some inductances at the edge of the tank, or do some fancy laser-scanning of the surface. I can easily see incorporating the continually-changing conditions into the calculations as taking a long time. And cylindrical Bessel functions are not so easily precomputed if you need 50 of them at a particular time. I'd think the easiest way to do that is to set up 50 analog circuits with the appropriate parameters and continuously feed in the water heights along the edge of the tank.

For applications... I can't answer this in full, since part of my research is sort of related. But for detecting things buried in the seafloor, ripples on the seafloor do some amazing things to signals. Having a reliable way to set up such ripples in the laboratory is very useful.

> And that can only be done with some sophisticated feedback as to what waves are present once they got the first character stationary, wouldn't they know the waves present? so you would have to pre-compute all your transitions, and stationary letters. I would guess it is soo much data, needed so fast, that they just didn't do the necessary hardware for a show yet.unless they are only able to get the character to hold form for a mSec, in that case your going to have darkness, and a strobe light to make

These scientists can apply an amazingly controlled level of force to a specific point on a 2-D surface across something a unpredictable as the surface of water. Imagine bringing this down to nanotechnology level, could the same principles allow someone to sculpt an object out of individual atoms from the center out?-Jason

Short answer: No. Long answer: No, you idiot. Can't you see the difference between a large pool of water and a small crystal of silicon, or whatever? Honestly, Slashdot seems to be full of scientifically illiterate morons at the moment.
Good thing rational, intelligent adults who are capable of civil discourse are not in short supply! To address the difference you noted about a large pool of water and a small crystal of silicon (or whatever), isn't it possible to consider displacing atoms by the calculate

Back in college, I toyed with the idea of doing something like this as my senior project. My name for it, at the time, was a "water hologram", which I think more-accurately describes what's going on. You're manipulating one or more wave sources in order to generate a specific pattern of constructive and destructive interference.

I'd like to see a video of it. I'm curious to see if the images are: A) constantly oscillating up and down, B) perpetually raised and not oscillating, or C) just there for a momen

I think this is somewhat related to CAT scans, but applied in reverse. My crude understanding of a CAT scan is that sensors are placed in a ring shape around the object to be scanned and a series of "slices" are scanned. For each "slice", this gives a set of axial views through the object (the 'A' in CAT). Bessel functions are the mathematical tool that let you convert the axial data - which is a kind of sum across a diameter - into data at each point in the circular cross section.

It seems they've reversed this process and solved for the axial data given the point-by-point data - e.g. the rasterized character.

By the way, CAT scans and Bessel functions are one of the examples of "abstract" math that later turns out to have practical application.

The picture [blogsmithmedia.com] seems to show about 60 solenoids around a small pool of water. When they're all clacking away they'd make one heck of a din. The writing looks amazing, but I can't see e.g. a hotel wanting this thing in the lobby unless it can be made very quiet.

Also, do you remember how yogic flying [victorybeforewar.com] made the news a few years back. The photos seemed to show these guys hovering in mid-air, but in fact they were just "bottom-hopping" up and down and someone clicked the shutter at the top of their bounce. I'd li

Here's a link to a PDF document [mes.co.jp] from Akiken's website that gives some more details about the project. Unfortunately I can't read Japanese, so maybe someo kind soul can provide a translation? However, the PDF does have some additional pics, taken in sequence. I'm not sure but it seems like the oscillation affect takes a few moments to build (the 15 to 30 seconds I'm guessing) and then momentarily generate the character.

The nature of water being fluid means it would be unlikely the character would remain for

So, you're telling me that Writing on Water can only do between 1/15th and 1/30th of a frame per second on your machine? Damn - don't you think it's about time that you upgraded your Wave Processing Unit?